This research will assess the effects of adolescent sexual activity on health and development across three domains: mental health, academic engagement, and risk behaviors. Adolescent sexual intercourse has clear and direct links to several aspects of physical health: the U.S. teen pregnancy rate is 71 (per 1000 girls 15-19), the teen birth rate is 42, and recent estimates indicate that one in four teen girls (38% of sexually experienced teen girls) have a sexually transmitted infection (STI). We know less about how sexual activity influences other outcomes that shape well-being in adolescence and at later stages in the life course. Prior research links adolescent sex to depression, disinterest in education, and risk behaviors like drug use, but the mechanisms underlying these associations remain ambiguous. Our research will examine how the norms that characterize the social world of adolescents moderate the relationship between their emergent sexual behavior and well- being. Our specific focus is on global and local norms that contribute to the normative context of sex. Global norms reflect general, societal expectations that are typically reinforced by parents and other sources of normative influence. These global norms are more accepting of sex among older teens, boys, and those in romantic relationships. Local norms, in contrast, originate in more immediate social settings and may reinforce, modify or repudiate global norms. We examine normative context at three levels, situating adolescents within friendship networks and within schools. The project has two aims. The first aim is to investigate if and how global norms about adolescent sex condition the association between sex and mental health, school engagement, and risky behavior. The second aim is to analyze the degree to which the influence of global norms is contingent on local norms of friends and schoolmates. We will employ multi-level models and utilize information from most of the data files in the large and comprehensive Add Health archive including saturated school samples and the Adolescent Health Academic Achievement Study. These data are uniquely suited to our analyses of multiple layers of norms and three domains of well-being. Coupled with existing knowledge about sexual behavior and physical health, our investigation will provide a comprehensive portrait of the effects of sex on health and well-being in adolescence. Our focus on normative context highlights an important milieu for promoting adolescent well-being that is rarely discussed in studies of teen sex or in policy circles.